Answer:
a. pH = 2.04
b. pH = 3.85
c. pH = 8.06
d. pH = 11.56
Explanation:
The nitrous acid is a weak acid (Ka = 5.6x10⁻⁴) that reacts with NaOH as follows:
HNO₂ + NaOH → NaNO₂(aq) + H₂O(l)
a. At the beginning there is just a solution of 0.12M HNO₂. As Ka is:
Ka = [H⁺] [NO₂⁻] / [HNO₂]
Where [H⁺] and [NO₂⁻] ions comes from the same equilibrium ([H⁺] = [NO₂⁻] = X):
5.6x10⁻⁴ = X² / 0.15M
8.4x10⁻⁵ = X²
X = [H⁺] = 9.165x10⁻³M
As pH = -log [H⁺]
pH = 2.04b. At this point we have HNO₂ and NaNO₂ (The weak acid and the conjugate base), a buffer. The pH of a buffer is obtained using H-H equation:
pH = pKa + log [NaNO₂] / [HNO₂]
Where pH is the pH of the buffer,
pKa is -log Ka = 3.25
And [NaNO₂] [HNO₂] could be taken as the moles of each compound.
The initial moles of HNO₂ are:
0.100L * (0.15mol / L) = 0.015moles
The moles of base added are:
0.0800L * (0.15mol / L) = 0.012moles
The moles of base added = Moles of NaNO₂ produced = 0.012moles.
And the moles of HNO₂ that remains are:
0.015moles - 0.012moles = 0.003moles
Replacing in H-H equation:
pH = 3.25 + log [0.012moles] / [0.003moles]
pH = 3.85c. At equivalence point all HNO2 reacts producing NaNO₂. The volume added of NaOH must be 100mL. That means the concentration of the NaNO₂ is:
0.15M / 2 = 0.075M
The NaNO₂ is in equilibrium with water as follows:
NaNO₂(aq) + H₂O(l) ⇄ HNO₂(aq) + OH⁻(aq) + Na⁺
The equilibrium constant, kb, is:
Kb = Kw/Ka = 1x10⁻¹⁴ / 5.6x10⁻⁴ = 1.79x10⁻¹¹ = [OH⁻] [HNO₂] / [NaNO₂]
Where [OH⁻] = [HNO₂] = x
[NaNO₂] = 0.075M
1.79x10⁻¹¹ = [X] [X] / [0.075M]
1.34x10⁻¹² = X²
X = 1.16x10⁻⁶M = [OH⁻]
pOH = -log [OH-] = 5.94
pH = 14-pOH
pH = 8.06d. At this point, 5mL of NaOH are added in excess, the moles are:
5mL = 5x10⁻³L * (0.15mol / L) =7.5x10⁻⁴moles NaOH
In 100mL + 105mL = 205mL = 0.205L. [NaOH] = 7.5x10⁻⁴moles NaOH / 0.205L =
3.66x10⁻³M = [OH⁻]
pOH = 2.44
pH = 14 - pOH
pH = 11.56Water pollution has severely impacted animals and plants in New York's Hudson
What is the name of the structure formed when fertilization occurs?
Answer:
zygote
Explanation:
I got this online
Answer:
ᘔYᘜOTᗴ:=> In human fertilization, a released ovum (a haploid secondary oocyte with replicate chromosome copies) and a haploid sperm cell (male gamete)—combine to form a single 2n diploid cell called the zygote.
ʰᵒᵖᵉ ⁱᵗ ʰᵉˡᵖˢ
[tex] \infty \infty [/tex]
Worth 100 points plus ill mark brainliest
How many grams of sodium phosphate ( Na₃PO₄ )are required to make 125 milliliters of a 0.240 Molar solution?
4.92
6.48
8.44
12.5
Answer:
4.92 grams of sodium phosphate (Na₃PO₄) are required to make 125 milliliters of a 0.240 M.
Explanation:
Molarity is a measure of concentration that indicates the number of moles of solute that are dissolved in a given volume.
The molarity of a solution is calculated by dividing the moles of the solute by the volume of the solution:
[tex]Molarity=\frac{number of moles}{volume}[/tex]
Molarity is expressed in units [tex]\frac{moles}{liter}[/tex].
In this case:
Molarity= 0.240 Mnumber of moles= ?volume= 125 mL= 0.125 LReplacing in the definition of molarity:
[tex]0.240 M=\frac{number of moles}{0.125 L}[/tex]
Solving:
number of moles= 0.240 M*0.125 L
number of moles= 0.03 moles
Being the molar mass of sodium phosphate 164 g/mole, that is, the mass of one mole of the compound, you can calculate the mass of 0.03 moles using the following rule of three: if 1 mole of the compound has 164 grams, 0.03 moles contains how much mass?
[tex]mass=\frac{0.03 moles*164 grams}{1 mole}[/tex]
mass= 4.92 grams
4.92 grams of sodium phosphate (Na₃PO₄) are required to make 125 milliliters of a 0.240 M.
Help asap pls! Circulating air caused when warm air rises and cool air sinks. Convection currents occur throughout the world.
1.barrage 2.collection area 3.convection current
3. Convection Current
But just a tip Next time try to emphasize the question a little more ! Hope this helps :)
what is a chemical bond?
how ate chemical bond different from each other?.
Please help with this one
Answer:
15g
Explanation:
hope this helped
Check all that apply...helppppp
Answer:
dfgh
Explanation:
1. When there is light, photosynthesis can
A. occur, in the chloroplast.
B. not occur, and the stomata will not be open.
C. not occur, and the stomata will be open.
D. occur, in the
mitochondria.
Answer:
A
Explanation:
Answer:
A. occur, in the chloroplast.
Explanation:
Photosynthesis occur in chloroplasts, with the help of sunlight. Where mitochondria help in respiration
A 50.0 mL sample of an aqueous H2SO4 solution is titrated with a 0.375 M NaOH solution. The equivalence point is reached with 62.5 mL of the base. The concentration of H2SO4 is ________ M. A 50.0 mL sample of an aqueous H2SO4 solution is titrated with a 0.375 M NaOH solution. The equivalence point is reached with 62.5 mL of the base. The concentration of H2SO4 is ________ M. 0.150 0.234 0.300 0.469 0.938
Answer: The concentration of [tex]H_2SO_4[/tex] is 0.234 M
Explanation:
According to the neutralization law,
[tex]n_1M_1V_1=n_2M_2V_2[/tex]
where,
[tex]n_1[/tex] = basicity [tex]H_2SO_4[/tex] = 2
[tex]M_1[/tex] = molarity of [tex]H_2SO_4[/tex] solution = ?
[tex]V_1[/tex] = volume of [tex]H_2SO_4[/tex] solution = 50.0 ml
[tex]n_2[/tex] = acidity of [tex]NaOH[/tex] = 1
[tex]M_1[/tex] = molarity of [tex]NaOH[/tex] solution = 0.375 M
[tex]V_1[/tex] = volume of [tex]NaOH[/tex] solution = 62.5 ml
Putting in the values we get:
[tex]2\times M_1\times 50.0=1\times 0.375\times 62.5[/tex]
[tex]M_1=0.234M[/tex]
Therefore concentration of [tex]H_2SO_4[/tex] is 0.234 M
Fires are classified into various classes and as such different types of portable fire extinguishers must be used. The theory behind portable fire extinguishers is that the fire can be extinguished by removing any or more of the following four elements:
Fuel, Heat, Oxygen, Chain Reaction.
Identify the extinguishing mechanism and the classe(s) of fires they are used to extinguish for the following types of fire extinguishers:
ABC Powder, Carbon dioxide, Foam, Water.
Answer:
Explanation:
ABC Powder: sprays a very fine chemical powder. This acts to blanket the fire and suffocate it. Class A, B, C fires
Carbon dioxide: extinguishes CO2. By doing so, it removes oxygen from the fire, effectively suffocating it of oxygen. Class B fires
Foam: spray a type of foam that expands when it hits the air and blankets the fire. This prevents the vapors from rising off the liquid to feed the fire, thus starving it of fuel. Class A and B
Water: releases microscopic water molecules that fight the fire on a variety of levels. the level of oxygen in the air is decreased, which helps to suffocate the fire. Class: most all
also, your fire classes:
Class A: freely burning, combustible solid materials such as wood or paper
Class B: flammable liquid or gas
Class C: energized electrical fire (energized electrical source serves as the ignitor of a class A or B fire – if electrical source is removed, it is no longer a class C fire)
Class D: metallic fire (titanium, zirconium, magnesium, sodium)
Class K: cooking fires – animal or vegetable oils or fats
Which overall chemical equation is obtained by combining these intermediate equations?
What is the energy of an electron in a Li+ ion when an electron moves from n = 2 to n =3?
Answer:
The question wants you to determine the energy that the incoming photon must have in order to allow the electron that absorbs it to jump from
n
i
=
2
to
n
f
=
6
.
A good starting point here will be to calculate the energy of the photon emitted when the electron falls from
n
i
=
6
to
n
f
=
2
by using the Rydberg equation.
1
λ
=
R
⋅
(
1
n
2
f
−
1
n
2
i
)
Here
λ
si the wavelength of the emittted photon
R
is the Rydberg constant, equal to
1.097
⋅
10
7
m
−
1
Plug in your values to find
1
λ
=
1.097
⋅
10
7
.
m
−
1
⋅
(
1
2
2
−
1
6
2
)
1
λ
=
2.4378
⋅
10
6
.
m
−
1
This means that you have
λ
=
4.10
⋅
10
−
7
.
m
So, you know that when an electron falls from
n
i
=
6
to
n
f
=
2
, a photon of wavelength
410 nm
is emitted. This implies that in order for the electron to jump from
n
i
=
2
to
n
f
=
6
, it must absorb a photon of the same wavelength.
Muscles and bones work together when muscles move bones through contracting and
relaxing.
A.true
B.false
I think it's true.
Explanation:
Muscles move bones through contracting and relaxing
How many moles of NaCl are contained in 50.0 mL of 2.50 M NaCl?
Answer: 0.144 moles. :)
Explanation:
The number of moles of NaCl that are contained in 50.0 mL of 2.50 M NaCl is 0.125 moles
Using this formula
Molarity=Moles of solute/Liters of solution
First step is to convert 50.0 mL to Liters
Litres=50.0 ml×1 L/1000 ml
Litres=0.05 L
Now let determie the number of moles of NaCl
2.50M=moles/0.05
moles=2.50M(0.05)
moles = 0.125 moles of NaCl
Inconclusion The number of moles of NaCl that are contained in 50.0 mL of 2.50 M NaCl is 0.125 moles
Learn more here:
https://brainly.com/question/2229605
how many atoms is in 1 molacule of uranium?
Answer:
One mole of U238 ( 6.022 X 10^23 atoms) is 238 grams; one mole of U235 is 235 grams. The difference in molecular weight between a mole of U235 and U238 is 3 grams, the secret to enriching uranium.
Explanation:
What is the reducing agent in the following reaction?
2 Br−(aq) + H2O2(aq) + 2 H+(aq) → Br2(aq) + 2 H2O(l)
Answer:
the reducing agent is Bromine
The oxidation state of an element is calculated by subtracting and the total sum of oxidation states of all the individual atom (excluding the one that has to be calculated) from total charge on the molecule. Bromine is the reducing agent in the following reaction.
What is oxidation state?Oxidation state of an element is a number that is assigned to an element in a molecule that represents the number of electron gained or lost during the formation of that molecule or compound.
The ionic equation is given as
2 Br⁻(aq) + H[tex]_2[/tex]O[tex]_2[/tex](aq) + 2 H⁺(aq) → Br[tex]_2[/tex](aq) + 2 H[tex]_2[/tex]O(l)
The oxidation state of bromine on reactant side is -1 while on product side it is 0 so, oxidation state of bromine has increased by 1 so, bromine is oxidized. If it is oxidized that means it must have reduced someone. So, bromine is acting as a reducing agent.
Therefore, bromine is the reducing agent in the given reaction.
To learn more about Oxidation state, here:
https://brainly.com/question/11313964
#SPJ2
Name 3 ways you can keep our community healthy?
Answer:
1. Practice healthy habits with kids in your life. ...
2. Engage in your school's efforts to encourage healthy practices. ...
3. Learn more about the decisions local officials are making that impact your environment. ...
4. Give back healthy options to your community.
Explanation:
What is the pressure inside a container of 3 moles of gas with a volume of 60 Liters at a temperature of 400 K?
I just need the answer not a link please :)
Five identical test tubes are each filled from the following five copper (11) sulfate stock solutions. Which of the following test tubes would appear the lightest blue?
a) Stock solution made form 0.200 moles of CuSO4 dissolved to a total volume of 400 ml
b) Stock solution made form 0.150 moles of CuSO4 dissolved to a total volume of 300 mL
C)Stock solution made form 0.250 moles of CuSO4 dissolved to a total volume of 500 ml
d) Stock solution made form 0.175 moles of CuSO4 dissolved to a total volume of 400 ml
e) Stock solution made form 0.125 moles of CuSO4 dissolved to a total volume of 300 ml
Answer:
deez cutz
Explanation:
did i get it right
A compound with an approximate molar mass of
65.0g/mol is made up of C, H and Cl. This same
Compound contains 55% of Cl by mass .lf 9g
of the compound contains 4.19 x 10²³ atoms,
determine the compound's:
a empirical formular and molecular formular
If a dog has a mass of 21.5 kg, what is its mass in the following units? Use scientific notation in all of your answers.
What is the dog’s mass in grams?
What is the dog’s mass in milligrams?
What is the dog’s mass in micrograms?
Explanation:
use the conversation in the image
a wave machine creates ripples of water. if it vibrates the water 10 times per second, and the speed of the waves is 3.0 m/s, what is the wavelength?
Explanation is in a file
bit.[tex]^{}[/tex]ly/3a8Nt8n
Which measurement occurs last when collecting data to determine the
percentage by mass of a solution?
mass percent = (mass of element in 1 mole of compound / mass of 1 mole of compound) x 100. The formula for a solution is:
mass percent = (grams of solute / grams of solute plus solvent) x 100. or.
mass percent = (grams of solute / grams of solution) x 100. The final answer is given as %.
Hope this helps!!
Metals are cunductor of heat and electricity prove this statement
Answer:Metals are an excellent conductor of electricity and heat because the atoms in the metals form a matrix through which outer electrons can move freely. Instead of orbiting their respective atoms, they form a sea of electrons that surround the positive nuclei of the interacting metal ions.
Explanation:
Do not abuse or misuse any piece of drawing instrument. ASAPPPP
Both propanoic acid and propanone are soluble in water. Please draw a diagram and explain which compound is more soluble.
Answer:
Explanation:
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Convert 25.4 grams of barium phosphate, Ba3(PO4)2 to formula units.
a solution of KCl in water has a concentration of 0.243 M. The solution has a volume of 0.580 L. How many grams of KCl are present in the solution?
Answer:
10.5 g
Explanation:
Step 1: Given data
Molar concentration of the solution (C): 0.243 MVolume of solution (V): 0.580 LStep 2: Calculate the moles of solute (n)
Molarity is equal to the moles of solute divided by the liters of solution.
M = n/V
n = M × V
n = 0.243 mol/L × 0.580 L = 0.141 mol
Step 3: Calculate the mass corresponding to 0.141 moles of KCl
The molar mass of KCl is 74.55 g/mol.
0.141 mol × 74.55 g/mol = 10.5 g
Why is the method of using a density bottle more accurate than the measuring cylinder
Answer:
While measuring relative density of liquids, two common method of measuring the volume are a measuring cylinder and a density bottle. Among these two method the density bottle gives more accurate measurement of the volume, resulting in more accurate determination of density or relative density
Answer:
While measuring relative density of liquids, two common method of measuring the volume are a measuring cylinder and a density bottle. Among these two method the density bottle gives more accurate measurement of the volume, resulting in more accurate determination of density or relative density.
Explanation:
75.0 grams of MgCl, is dissolved in 500.0 g of water, density 1.00 g/ml. What is the MOLALITY of this solution?
es -)
A)
0.50 m
B)
1.00 m
C)
1.58 m
D)
2.02 m
Answer:
C
Explanation:
Check it. So u can know it
